TCC Check
The torque converter clutch (TCC) is designed to eliminate power loss during cruise driving conditions. When the TCC is applied, the conventional fluid coupling between the engine and transmission is replaced by a straight-through mechanical coupling. The heart of the system is the TCC solenoid located inside the transmission which is controlled by the ECM. The ECM completes the ground to activate the TCC solenoid for clutch engagement.
The ECM completes the circuit whenever the TPS exceeds a calibrated value for throttle opening.
NOTE:
The following step numbers refer to the numbers in the accompanying flow chart(s).
- This step checks for complete circuit from ignition through solenoid, up to test point. The test light should be on because the ECM has not completed the circuit yet.
- This step checks the ECM's ability to complete the circuit to ground to energize the TCC solenoid and engage the TCC. The test light should go out when the ECM completes the circuit.
- This checks the TPS signal. If signal to ECM is correct voltage, fault is in ECM connection or ECM. If TPS signal to ECM is not correct voltage, proper operation will not occur.
- This checks for ground in circuit to ECM terminal "A2". The light should be off.
- This checks for ignition voltage to terminal "A" of TCC connector. Light should be on.
- This checks for complete circuit from ignition to ground via TCC test terminal in ALDL connector. Light should go on if harness is good.